Insular Cortical Projections to Functional Regions of the Striatum Correlate with Cortical Cytoarchitectonic Organization in the Primate

Abstract

We examined the striatal projections from different cytoarchitectonic regions of the insular cortex using anterograde and retrograde techniques. The shell and medial ventral striatum receive inputs primarily from the agranular and ventral dysgranular insula. The central ventral striatum receives inputs primarily from the dorsal agranular and dysgranular insula. Projections to the central ventral striatum originate from more posterior and dorsal insular regions than projections to the medial ventral striatum. The dorsolateral striatum receives projections primarily from the dorsal dysgranular and granular insula. These results show that cytoarchitectonically less differentiated (agranular) insular regions project to the ventromedial "limbic" part of the ventral striatum, whereas more differentiated (granular) insular regions project to the dorsolateral "sensorimotor" part of the striatum. The finding that the ventral "limbic" striatum receives inputs from less differentiated regions of the insula is consistent with the general principle that less differentiated cortical regions project primarily to the "limbic" striatum. Functionally, the ventral striatum receives insular projections primarily related to integrating feeding behavior with rewards and memory, whereas the dorsolateral striatum receives insular inputs related to the somatosensation. Information regarding food acquisition in the insula may be sent to the intermediate area of the striatum.

Striatal Morphology is Associated with Tobacco Cigarette Craving

“…The ventral anterior putamen not only is larger in occasional stimulant users (Mackey et al, 2014), but this striatal subregion receives projections from the insula (Chikama et al, 1997), a brain region implicated in maintaining nicotine dependence (Naqvi et al, 2007) and smoking cue-reactivity (Janes et al, 2010). The insula and striatum may interact to mediate nicotine dependence, as damage to both of these brain regions disrupts smoking (Gaznick et al, 2014), and suggests a possible link between ventral anterior putamen deformations and cue-reactivity due to striatal-insula interactions.…”

Insular hypocretin transmission regulates nicotine reward

“…In the rat brain, the insula is comprised of a dorsally located granular region, a ventral agranular region, and the dysgranular region located between these areas. Previously it was shown that the dorsolateral striatum, a brain area heavily implicated in the expression of habitual responding for drugs of abuse (26), receives dense innervation from the granular and dysgranular portions of insula (25). Moreover, temporary inactivation of the granular insula revers-ibly disrupted amphetamine seeking in rats tested in a place conditioning procedure (26).…”

Differential Role of Muscarinic Transmission within the Entorhinal Cortex and Basolateral Amygdala in the Processing of Irrelevant Stimuli

“…BLA and PFC relay to the core the information on the motivational value of the CS, which promotes switching to respond according to the CS-reinforcement contingency. Inputs from the PFC and BLA to NAC core, and from the EC and IC to NAC shell (Brog et al, 1993;Chikama et al, 1997;Weiner, 2003;Feldon, 1997, Jeanblanc et al, 2004), compete to enhance and reduce, respectively, DA release in the NAC core. BLA, EC, IC, and PFC receive cholinergic afferents from the BF, providing the substrate for cholinergically mediated modulation of these regions' inputs to the NAC.…”